title: The use of a three-dimensional imaging model to optimize the operative separation of pygopagus conjoined twins.
abstract: BACKGROUND
  The surgical management of conjoined twins has evolved to the point that elective operative separation can safely be performed in the majority. Cross-sectional imaging is invaluable to accurately delineate the site of union and configuration of shared organ systems prior to surgery. The use of three-dimensional modeling also dramatically improves the planning process and assists in intraoperative decision-making. We present a case of pygopagus conjoined twins who underwent successful operative separation at 19 months of age with the aid of such technology.
  
  
  METHODS
  A three-dimensional computer animation was created by Medical Modeling LLC (Golden, CO, USA) from representative cross-sectional CT and MR images. The complete animation is available at http//www.medicalmodeling.com/ahmed. A plasticized bony pelvic model, accurate to 1mm, was also created using similar technology.
  
  
  RESULTS
  The three-dimensional animation and pelvic model were utilized during both the planning and operative phases of the separation. The shared pelvic soft-tissue anatomy consisted of a conjoined penis with four corporal bodies, and a posteriorly conjoined urethra subtending two separate bladders and outlets. The rectum was conjoined approximately 2 cm proximal to the single anus. A blind-ending hindgut remnant was also documented by the animation. Following operative separation, both twins recovered uneventfully.
  
  
  CONCLUSIONS
  Three-dimensional computer animation technology was extremely accurate intraoperatively and predicted exactly which shared organs would sequentially be encountered as the dissection commenced. It significantly reduced the overall operative time and provided critical intraoperative anatomic information. We recommend that this readily available technology be utilized for any patient requiring extensive reconstructive surgery.
authors.affiliation: The Hospital for Sick Children, Division of Urology, Department of Surgery, University of Toronto, M299-555 University Avneue, Toronto, Ontario, Canada. anthony.cook@sickkids.ca
authors.forename: Anthony
authors.initials: A
authors.lastname: Cook
authors.forename: Amin
authors.initials: A
authors.lastname: El-Gohary
authors.forename: Antoine E
authors.initials: AE
authors.lastname: Khoury